Move tsm.driver.local_scheduler to torchx.schedulers

Summary:
* Move test resources to torchx.schedulers.fb.resources
* Move tsm.local_scheduler to torchx.schedulers
* Move tsm.image_fetcher to torchx.schedulers
* Move test_utils to torchx.schedulers
* Fix many pyre errors

Reviewed By: kiukchung

Differential Revision: D28447387

fbshipit-source-id: 044b6bacc6537122cbbd64b3db0d656a8d0944ab

Author: aivanou